I utilise a Haringey UBR and found about a TX fault with the one I connect to. This fault was raised internally within VM in July but nothing mentioned by VM publically. I found out when complaining in August about steady reductions in bandwidth. I am getting download speeds of between 20 kilo
bytes to 400 kilo
bytes per second on a 20 mega
bit connection. I should get around 1.6 to 1.7 mega
bytes per second going by past experience.
After a bit of back and forth, the fault will not be fixed until November (UBR's are expensive to replace) and I am getting £27 per month discount from my cable bill. Fair play to VM for offering this. However, if I hadn't complained and kicked up a fuss, I wouldn't have been passed onto a "Customer Concern" rep (read: retention).
Moral of the story is - moan like nympho with tourettes syndrome. Make sure you get put through to "Customer Concern" if the helldesk doesn't sort you out. I found that complaining online via VM's website got a better response and I didn't have to spend hours in a call queue.
Edit: This ticket was raised this afternoon, would this affect Barnet?
http://status-cable.virginmedia.com/...?ticket=828480
Edit 2: VM are currently carrying out UBR capacity upgrades. Check here
http://status-cable.virginmedia.com/...maintenance.do to see if maintenance has affected your service - could be a clue.
Good luck.